SEARCH · PubMed Health

Results for “Muscle Strength”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 919 records · Page 51Linked to original sources

PubMed1999

Cross-education of muscle strength is greater with stimulated than voluntary contractions.

Cross-education enhances the performance of muscles not directly involved in the chronic conditioning of the muscles in a remote limb. Substantial cross-education occurs after training with eccentric contractions or with contractions evoked by electromyostimulation (EMS). Since during EMS and eccentric contractions, skin and muscle afferents are activated that have excitatory effects on contralateral homologous muscles, it was hypothesized that exercise training with stimulated vs. voluntary eccentric contractions would lead to greater cross-education. Thirty-two women were randomly assigned to a voluntary (Vol), an EMS, or remote EMS (rEMS) exercise group and performed 840 voluntary or stimulated eccentric contractions over 6 weeks. All subjects, including nonexercising controls (Con), were tested pre- and posttraining for maximal voluntary and stimulated isometric and eccentric quadriceps strength. Ipsilateral voluntary and stimulated forces increased in all groups. Changes in EMG activity paralleled those in voluntary force in each limb. No changes occurred in grip strength. The great contra- and ipsilateral strength gains after EMS training were most likely related to an additive effect of EMS and muscle lengthening.

Adult↗

PubMed1995

Role of agonist and antagonist muscle strength in performance of rapid movements.

Six subjects performed rapid self-terminated elbow movements under different mechanical conditions prior to, and 5 weeks after an elbow extensor strengthening programme. Despite the large difference in the strengths of elbow flexors and extensors, the pretest did not demonstrate significant differences between the movement time of flexion and extension movements performed under the same mechanical conditions. The results obtained in the posttest demonstrated a decrease in movement time (i.e. an increase in movement speed) in both elbow flexion and extension movements under some mechanical conditions. In addition, flexion movements demonstrated a relative increase in the acceleration time (acceleration time as a proportion of the movement time). It was concluded that the strength of both the agonist and antagonist muscles was important for the performance of rapid movements. Stronger agonists could increase the acceleration of the limb being moved, while stronger antagonists could facilitate the arrest of the limb movement in a shorter time, providing a longer time for acceleration.

Adult↗

PubMed1990

Lip-length and snout indices: methods for quantitative assessment of peri-oral facial muscle strength.

Two simple bedside methods for the assessment of perioral muscle function are described. Using a marking gauge, the width of the mouth can be measured easily and accurately. Lip-length (LL) and snout (S) indices are expressions of the degree to which the width of the mouth can be lengthened or shortened. Facial muscle weakness as present in patients with various neuromuscular diseases results in low values for both indices. LL- and S-indices are measured by 3 observers in 19 healthy volunteers. Interobserver variation is negligible for the LL-index and large for the S-index. Intraobserver variation is moderate for both indices but slightly smaller for the LL- than for the S-index. The LL-index is suited for the assessment of changes in peri-oral musculature in longitudinal investigations.

Adult↗

PubMed2007

Functional assessment and muscle strength before and after reconstruction of chronic anterior cruciate ligament lesions.

PURPOSE: The goal of this study was to evaluate strength and functional capacity before and after anterior cruciate ligament (ACL) reconstruction to determine the influences of preoperative strength deficit, graft type, and gender, as well as their clinical relevance in predicting postsurgical recovery and determining the postoperative rehabilitation program. METHODS: This was a retrospective review of prospectively collected uniform data from a group of 191 patients undergoing ACL reconstruction. We assessed functional capabilities and strength of the quadriceps and hamstring at 60 degrees/s and 180 degrees/s by use of a Cybex II dynamometer (Lumex, Ronkonkoma, NY) before and 6, 9, and 12 months after surgery. RESULTS: There was a preoperative quadriceps strength deficit and a decreased limb symmetry index in patients with an ACL deficiency. This strength deficit increased postoperatively, with the highest measured deficit occurring at 6 months postoperatively and a clear improvement from 6 to 12 months. Functional assessment showed identical development. There was a statistically significant relation between an increased quadriceps strength deficit preoperatively and poor early postoperative functional performance. For the bone-patellar tendon-bone (BPTB) group, there was an increased quadriceps strength deficit compared with the semitendinosus and gracilis tendon (STG) group, and the STG group had an increased hamstring strength deficit on postoperative testing. The postoperative hamstring strength deficit is significantly increased in female patients. CONCLUSIONS: All of these data suggest that quadriceps strength deficit is related to the ACL injury and is increased by ACL reconstruction. Even 1 year after ACL reconstruction, a quadriceps strength deficit of almost 20% persists. Flexion strength is within the normal range before and after surgery. These results are influenced by graft choice, with a higher quadriceps strength deficit for BPTB grafts. STG grafts induce a higher hamstring strength deficit compared with BPTB grafts. Functional assessment is improved at 9 and 12 months postoperatively compared with preoperatively regardless of graft type. However, an increased preoperative quadriceps strength deficit results in a lower limb symmetry index at 6 and 9 months postoperatively. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Adolescent↗

PubMed2002

The effects of accentuated eccentric loading on strength, muscle hypertrophy, and neural adaptations in trained individuals.

The purpose of this study was to compare the strength and neuromuscular adaptations for dynamic constant external resistance (DCER) training and dynamic accentuated external resistance (DAER) training (resistance training employing an accentuated load during eccentric actions). Male subjects active in resistance training were assigned to either a DCER training group (n = 10) or a DAER training group (n = 8) for 9 weeks. Subjects in the DCER group performed 4 sets of 10 repetitions with a load of 75% concentric 1 repetition maximum (RM). Subjects in the DAER group performed 3 sets of 10 repetitions with a concentric load of 75% of 1RM and an eccentric load of approximately 120% of concentric 1RM. Three measures reflecting adaptation of elbow flexors and extensors were recorded pretraining and posttraining: concentric 1RM, muscle cross-sectional area (CSA), and specific tension. Strength was assessed at midtraining periods. No significant changes in muscle CSA were observed in either group. Both training groups experienced significant increases in concentric 1RM and specific tension of both the elbow flexors and extensors, but compared with DCER training, DAER training produced significantly greater increases in concentric 1RM of the elbow extensors. These results suggest that, for some exercises, DAER training may be more effective than DCER training in developing strength within a 9-week training phase. However, for trained subjects, neither protocol is effective in eliciting muscle hypertrophy.

Adaptation, Physiological↗

PubMed2003

Effect of 6-month whole body vibration training on hip density, muscle strength, and postural control in postmenopausal women: a randomized controlled pilot study.

UNLABELLED: High-frequency mechanical strain seems to stimulate bone strength in animals. In this randomized controlled trial, hip BMD was measured in postmenopausal women after a 24-week whole body vibration (WBV) training program. Vibration training significantly increased BMD of the hip. These findings suggest that WBV training might be useful in the prevention of osteoporosis. INTRODUCTION: High-frequency mechanical strain has been shown to stimulate bone strength in different animal models. However, the effects of vibration exercise on the human skeleton have rarely been studied. Particularly in postmenopausal women-who are most at risk of developing osteoporosis-randomized controlled data on the safety and efficacy of vibration loading are lacking. The aim of this randomized controlled trial was to assess the musculoskeletal effects of high-frequency loading by means of whole body vibration (WBV) in postmenopausal women. MATERIALS AND METHODS: Seventy volunteers (age, 58-74 years) were randomly assigned to a whole body vibration training group (WBV, n = 25), a resistance training group (RES, n = 22), or a control group (CON, n = 23). The WBV group and the RES group trained three times weekly for 24 weeks. The WBV group performed static and dynamic knee-extensor exercises on a vibration platform (35-40 Hz, 2.28-5.09g), which mechanically loaded the bone and evoked reflexive muscle contractions. The RES group trained knee extensors by dynamic leg press and leg extension exercises, increasing from low (20 RM) to high (8 RM) resistance. The CON group did not participate in any training. Hip bone density was measured using DXA at baseline and after the 6-month intervention. Isometric and dynamic strength were measured by means of a motor-driven dynamometer. Data were analyzed by means of repeated measures ANOVA. RESULTS: No vibration-related side effects were observed. Vibration training improved isometric and dynamic muscle strength (+15% and + 16%, respectively; p < 0.01) and also significantly increased BMD of the hip (+0.93%, p < 0.05). No changes in hip BMD were observed in women participating in resistance training or age-matched controls (-0.60% and -0.62%, respectively; not significant). Serum markers of bone turnover did not change in any of the groups. CONCLUSION: These findings suggest that WBV training may be a feasible and effective way to modify well-recognized risk factors for falls and fractures in older women and support the need for further human studies.

Aged↗

PubMed1999

[Muscle strength and gait patterns of depressed people].

BACKGROUND: Gait characteristic and muscle power are often described in the clinical literature but with little empirical support. We assessed some parameters of gait and muscle power using simple and standardized methods within a framework based principally on classic clinical observations of depression. METHOD: 20 depressed inpatients were examined with standard tests of isometric muscle power and gait parameters, which measure step length, average walking speed, maximal walking speed, and three-minute walk distance. The results were compared with those of 20 matched healthy controls. The examination procedure was repeated after a three week period of inpatient treatment and significant symptomatic improvement. RESULTS: As predicted by our hypothesis depressed patients' muscle power and gait characteristics differed clearly from normal controls. Significant improvements after 3 weeks of inpatient treatment were found above all in extension of the knee and extension of the elbow tests as well as in all measures of our gait analysis. However, all gait parameters still differed significantly from those of healthy controls. CONCLUSIONS: Using simple but reliable tests which were used for the first time in psychiatry we examined certain relationships between depression and motor function in a moderately to severely depressed inpatient sample.

Case-Control Studies↗

PubMed2001

Angiotensin-I converting enzyme genotype-dependent benefit from hormone replacement therapy in isometric muscle strength and bone mineral density.

Low bone mineral density (BMD) and muscle weakness are major risk factors for postmenopausal osteoporotic fracture. Hormone replacement therapy (HRT) reverses the menopausal decline in maximum voluntary force of the adductor pollicis and reduces serum angiotensin-I converting enzyme (ACE) levels. The insertion (I) allele of the ACE gene polymorphism is associated with lower ACE activity and improved muscle efficiency in response to physical training. Therefore, we examined whether the presence of the I allele in postmenopausal women would affect the muscle response to HRT. Those taking HRT showed a significant gain in normalized muscle maximum voluntary force slope, the rate of which was strongly influenced by ACE genotype (16.0 +/- 1.53%, 14.3 +/- 2.67%, and 7.76 +/- 4.13%, mean +/- SEM for II, ID, and DD genotype, respectively; P = 0.017 for gene effect, P = 0.004 for I allele effect). There was also a significant ACE gene effect in the response of BMD to HRT in Ward's triangle (P = 0.03) and a significant I allele effect in the spine (P = 0.03), but not in the neck of femur or total hip. These data suggests that low ACE activity associated with the I allele confers an improved muscle and BMD response in postmenopausal women treated with HRT.

Bone Density↗

PubMed2006

[Muscle strength and mobility of nerve processes among women judoists taking into account their menstrual cycle].

The problem of female sports is considered foremost importance and attract vivid attention of scientists and coaches as well. This problem requires special research in order to establish effective means for high sportive achievements by the sports women, however, without deteriorating their health. Analysis of the obtained results showed that physical characteristics were changed in the process of permanent training. Sports women's loading should be increased step-by-step, in accordance with the level of functional possibilities and menstrual period. In 1,3 and 5 phases of menstrual cycle, physical activities have to be optimal and during the systematic exercises well answer supportive effect and in 2,4 menstrual cycles, the physical exercises may be maximal. Correct allocation of exercises activities considering the menstrual cycle gives the trainer possibility to train the sportsmen and enhance the sport effect.

Central Nervous System↗

PubMed2006

Effect of home mechanical ventilation on inspiratory muscle strength in COPD.

BACKGROUND: The mechanism responsible for chronic hypercapnic respiratory failure (HRF) in patients with COPD remains unclear. In this study, we tested the hypothesis that chronic HRF in patients with COPD is associated with low-frequency fatigue (LFF) of the diaphragm. METHODS: To test this hypothesis, we measured the twitch transdiaphragmatic pressure (Tw Pdi) elicited by stimulation of the phrenic nerves in 25 patients with chronic HRF (mean [+/- SD] Paco(2), 55.2 +/- 5.2 mm Hg) due to COPD before and 2 months after the initiation of noninvasive mechanical ventilation (NIV) [pressure-cycled ventilation with inspiratory positive airway pressure of 19.0 +/- 2.5 cm H(2)O]. We reasoned that had LFF been present, Tw Pdi should rise after effective NIV. RESULTS: The treatment compliance with NIV was good (median of machine usage was 7.1 h per night). Paco(2) decreased from 55.2 +/- 5.2 to 48.8 +/- 5.9 mm Hg (p < 0.001), and Pao(2) increased from 53.1 +/- 5.9 to 57.7 +/- 7.0 mm Hg (p = 0.007). Mean Tw Pdi at baseline was 11.1 +/- 6.6 cm H(2)O and after treatment was 11.7 +/- 7.2 cm H(2)O (not significant). Also, maximal static inspiratory mouth pressure did not change significantly (44.3 +/- 15.9 cm H(2)O vs 46.5 +/- 19.7 cm H(2)O). CONCLUSION: LFF of the diaphragm does not accompany chronic HRF in patients with COPD.

Aged↗

PubMed1996

Quantitative measure of muscle strength and size in chronic alcoholism: an early indication of tissue damage.

We measured quadriceps strength and thickness in 101 male alcoholic patients and in 58 controls in order to investigate the force-size relationships of skeletal muscle in an alcoholic population. The relationship of these parameters with the duration of alcoholism, nutritional status and biochemical and haematological markers of heavy chronic alcohol use was investigated. Alcohol consumption of more than 42 standard drinks (420 g alcohol) per week for at least 5 years is associated with muscle weakness and wasting. There was no evidence of under-nutrition in these alcoholic subjects and muscle wasting occurred independently of peripheral neuropathy, a history of muscle pain, abnormalities of liver enzymes and elevation of mean red cell corpuscular volume. Quantitation of muscle size and strength in heavy drinkers may provide a useful early indicator of health impairment in alcoholics.

Journal Article↗

PubMed1997

Growth hormone secretagogue increases muscle strength during remobilization after canine hindlimb immobilization.

Twenty-two beagles were divided into two equal groups, and the right hindlimb of each animal was immobilized at 105 degrees of knee flexion by external fixation. After 10 weeks of fixation, the device was removed, allowing free mobility for the following 5 weeks. Each day throughout the 15 weeks, one group received a growth hormone secretagogue (treatment) at a dose of 5 mg/kg, and the other received a lactose placebo (control). At weeks 0, 10, and 15, strength as indicated by maximum isometric extension torque was measured in the right hindlimb, biopsies of the vastus lateralis muscle were taken, and the dogs were weighed. Weekly blood samples were analyzed for insulin-like growth factor-1, blood urea nitrogen, and creatine phosphokinase. Between weeks 0 and 10, tetanic torque declined by about 60% (p < 0.001) in both groups, with no significant difference between the groups (p > 0.7). Between weeks 10 and 15, tetanic torque in the treated group increased by 0.81 Nm; this was significantly greater than the increase of 0.25 Nm in the placebo group (p < 0.05). The diameters of slow (type-1) and fast (type-2) fibers measured from the vastus lateralis muscle followed the same trend. At all time points, fiber diameter correlated strongly with torque; this argues against nonmuscular causes such as nerve injury for strength loss. The mean levels of insulin-like growth factor-1 increased 100% by week 4 in the treated group and remained elevated by about 60% throughout the experiment. Levels of insulin-like growth factor-1 in the placebo group decreased 30% within week 1 and remained depressed throughout the experiment. Our interpretation of these data suggests that the growth hormone secretagogue elevated levels of serum insulin-like growth factor-1, which in turn increased the size and strength of the quadriceps muscle during remobilization. These data may ultimately have therapeutic application to humans during rehabilitation after prolonged inactivity.

Animals↗

PubMed2000

Depressed mood and body mass index as predictors of muscle strength decline in old men.

OBJECTIVE: To study depressed mood as a predictor of strength decline within body weight categories over a 3-year follow-up period. DESIGN: A prospective cohort study over 3 years. SETTING: Honolulu, Hawaii. PARTICIPANTS: The subjects were 2275 men participating in the Honolulu Heart Program with an average age of 77.1 years (range 71-92 years), who were not cognitively impaired at baseline (Exam 4), and who participated in maximal hand grip strength measurements at baseline and 3 years later (Exam 5). MEASUREMENTS: Hand grip strength was measured using a dynamometer. Depressive symptoms were studied using an 11-item version of Center for Epidemiologic Studies Depression Scale with 9 as a cutoff. Body weight categories were formed on the basis of body mass index (BMI) (BMI = weight/height2; underweight: BMI < 20; normal weight: BMI 20-24.99, overweight: BMI > or = 25). MAIN RESULTS: At baseline, 9.4% of the participants were rated as having depressed mood. The mean individual strength change over 3 years was - 6.9% (standard deviation 14.0). Steep strength decline was determined as losing > or = 14% (lowest quartile). The proportions of those with steep strength decline in the groups based on combined distributions of BMI and depressed mood were: underweight/ depressed (n = 22) 41%, underweight/not depressed (n = 200) 28%, normal weight/depressed (n = 127) 30%, normal weight/not depressed (n = 1181) 25%, overweight/depressed (n = 55) 31%, overweight/not depressed (n = 675, referent) 21%. After adjusting for baseline strength, age, height, sociodemographic variables and diseases, the odds ratio for steep strength decline was more than four times greater among those who were depressed and underweight, and twice as great among people who were depressed and normal weight compared with those who were nondepressed and overweight. The risks of nondepressed under- and normal weight people and depressed overweight people did not differ from the reference group. CONCLUSIONS: Depressed mood was associated with increased risk of steep strength decline, in particular in older men with low body weight. Low body weight in combination with depressed mood may be an indicator of frailty or severe disease status that leads to accelerated strength loss and disability.

Aged↗

PubMed1995

Normal inspiratory muscle strength is restored more rapidly after laparoscopic cholecystectomy.

Respiratory complications after laparotomy cholecystectomy may result from generalised muscle weakness and fatigue, or from reduced respiratory muscle function secondary to an upper abdominal incision. In a prospective study we compared maximal inspiratory effort (Pimax/mmHg) and dominant hand grip strength (kPa) (expressed as a percentage of zero hour value) in patients undergoing open cholecystectomy (OC) (n = 12), laparoscopic cholecystectomy (LC) (n = 25) and a control group of patients undergoing lower limb surgery (n = 12). Of the 12 OC patients, three suffered respiratory complications: two had atelectasis and one a chest infection, compared with no such complications in the other two groups (P < 0.05). Pimax decreased postoperatively in all groups (P < 0.05) and had returned to normal by 48 h in the LC and control groups. In contrast, in the OC group Pimax fell from 112.5 +/- 17.8 mmHg to as low as 81.3 +/- 16.5 mmHg at 72 h and only returned to preoperative levels at 120 h. The hand grip strength fell significantly in all groups at 24 h (P < 0.05) but normal levels were achieved again by 48 h in all groups, and there was no significant difference in the hand grip strength between the groups over the 5 days. These results suggest that generalised muscle fatigue after surgery is similar after open and laparoscopic cholecystectomy. Open cholecystectomy does, however, cause a more prolonged reduction in respiratory muscle function and this is likely to contribute to the higher incidence of respiratory complications in this group of patients.

Adult↗

PubMed1978